Abstract

Field and laboratory investigations of basal Belly River sediments along the outcrop belt of the southern and central Alberta Foothills show a predictable facies sequence with characteristic sedimentary structures, textures, detrital composition and diagenesis. This facies sequence consists of shale and interstratified fine-grained sandstones at the base, followed by horizontal and low angle cross-stratified sandstones that are capped by coaly mudstones or scour-fill channel sandstones. A comparison of these results with data from core samples shows that many of these facies can be recognized in the subsurface, even though only a limited data base in the form of core and cuttings is available. The study reveals that the fine to medium grained, moderately to well sorted stream-mouth bar and distributary channel sands of the basal Belly River Formation are the best exploration targets, although carbonate and clay cementation constrain the reservoir value of some of these sands.